Case 6: Acute Ischaemic Stroke

Question 1

Differentiate types of Cerebrovascular disease:

• TIA (transient ischaemic attack)
• Ischaemic stroke
• Haemorrhagic stroke

Answer 1

Transient Ischaemic Attack (step before a stroke)
○ Warning sign that patient is at high risk of having a full stroke
○ Stroke symptoms (neurological deficit) that disappear within minutes (24 hours)
○ Without evidence of cerebral infarction
○ Loss of focal brain (or eye) function
○ Temporary loss of blood flow to brain/eye
○ Usually lasts 10-20 mins (<24 hrs) - symptoms completely disappear
○ Same causes as Ischaemic stroke (arterial disease, embolism, reduced cerebral perfusion pressure)

Ischaemic Stroke (blockage) - majority
○ Clot from neck or heart –> Middle cerebral artery stem blocked –> clot stops blood flowing to the brain —> reduce blood flow to brain downstream from clot
○ Brain starts dying after a few minutes
○ Blood vessels from top of other arteries = collateral flow (keep hypo perfused brain alive)
- However, overtime –> collateral arteries fail = infarct –> enlarges and form perfusion lesion
○ Result of cardioembolic or atherosclerotic arterial disease

Haemorrhagic Stroke (bleed)

• When blood vessel bursts suddenly - cause blood to leak in and around brain
• Blood on brain can lead to swelling –> serious problem (may need surgery)

a) Intracerebral Haemorrhage
- Artery bursts - small penetrating vessels in brain
- Brain small vessels: weakening of walls

b) Subarachnoid Haemorrhage
- Rupture of intracranial aneurysms contained within subarachnoid space surrounding brain
- Blood collects on outside of brain
- Thunderclap headache
- Slowly become more confused + lose consciousness

Question 2

Pathophys of ischaemic stroke

Answer 2

○ Caused by build up of fatty material in blood vessels
○ Fatty build up may lead to clot = blocks blood supply
○ Clot may occur within brain or can travel from another part of the body to brain
- Blood vessels in neck
- Or clots from the heart - may happen when you have irregular heartbeat/AF (atrial fibrillation)

Question 3

Clinical presentation (signs + symptoms) of TIA and Ischaemic stroke

Answer 3

○ Common clinical features

- FAST 
- Face -can person smile? Has mouth or eye drooped?
- Arm - or leg weakness - can person raise both arms
- Speech - can person speak clearly and understand what you say
- Time - call 111

○ Droopy face 
○ Weakness in arms and legs 
○ Difficulty speaking
○ Changes to vision 
○ Loss of balance 
○ Confusion 
○ Memory loss 

Diagnostic investigations
○ CT scans (compute tomography) - area of haemorrhage clearly visible and can detect ischaemic stroke
○ CT angiography: see any atherosclerosis or narrowing of arteries
○ MRI (magnetic resonance imaging) - more sensitive in detecting early ischemia
- More time consuming than CT scan
○ BP, ECG, urea, electrolytes, blood glucose, cholesterol, full blood count, inflammatory markers, thyroid function, erythrocyte sedimentation rate
ECG abnormalities - may suggest cardiac origin of thrombus, atrial fibrillation

Question 4

Inclusion + exclusion criteria for thrombolysis in acute ischaemic stroke

Answer 4

○ If ischaemic stroke (blockage) is detected within first few hours = thrombolysis can be given

Exclusion Criteria
○ Patients w high risk of serious bleeding
○ Risk of haemorrhage outweighs benefits of thrombolysis

Inclusion criteria:
○ Age 18 – 85 years
○ Clinical diagnosis of ischaemic stroke causing measurable neurological deficits
○ Clearly defined onset of symptoms within three hours of treatment initiation (a patient must not have woken from sleep with symptoms)
○ Patient able to undergo CT before tPA Administration

Exclusion criteria are numerous, some examples are:
○ Coma
○ Minor or non-disabling stroke symptoms
○ History of stroke in previous 12 weeks
○ Myocardial infarction within the past 30 days
○ Conditions involving increased risk of bleeding
- e.g. recent trauma, ulcerative wounds, thrombocytopenia
○ GI or genitourinary bleeding within last 21 days or structural ○ GI malignancy
○ Unable to maintain BP <185/110 despite aggressive antihypertensive treatment

Question 5

How is dose of alteplase calculated + administered for treatment of acute ischaemic stroke?

Answer 5

○ Intravenous alteplase administration
○ Dose of 0.9 mg/kg - maximum 90mg
○ For patients with potentially disabling ischaemic stroke within 4.5 hours of onset
○ Short half life of 5 minutes - administered as initial IV bolus (10% of total dose) - high risk drug for bleeds
○ Followed by remaining 90% - infused over 60 minutes

Question 6

Describe main side effects + monitoring parameters after thrombolysis

Answer 6

Side effects:
○ Major bleeding in brain (intracerebral haemorrhage)
○ Kidney damage in patients w kidney disease
○ Severe hypertension
○ Severe blood loss/internal bleeding
○ Bruising or bleeding at site of thrombolysis
○ Damage to blood vessels
○ Fragments of clot may migrate to other vessels and cause obstruction
○ Increased risk of bleeding in pregnant women, elderly + people with bleeding disorders
○ Increased risk for infection

Monitoring:

• Monitor neurological status and vital signs
• Every 15 minutes for first 2 hours
• Every 30 minutes for next 6 hours
• Every hour thereafter up to 24 hrs post IV
• Blood pressure monitoring
• Blood pressure (BP) monitoring during treatment administration and up to 24 hours is necessary;
• IV antihypertensive therapy is recommended if systolic BP > 180 mmHg or diastolic BP > 105 mmHg.

Question 7

Prevention of secondary ischaemic stroke - antiplatelet regimens

Answer 7

Acute antiplatelet therapy with aspirin for ischaemic stroke
○ After exclusion of haemorrhagic stroke by repeat imaging
○ aspirin (150–300 mg) is given as early as possible
- although delayed one or two days if thrombolysis is given.
○ Aspirin reduces the risk of death and recurrent stroke.
○ It is recommended that aspirin is continued as part of a long-term antithrombotic treatment regimen. - for up to 14 days
○ If patient dysphagic - administer using enteral feeding tube or via rectal route

Secondary prevention - all are insignificantly different when looking at person’s risk of having another stroke

• Clopidogrel alone (increased risk of bleeding)
• Low dose aspirin + dipyridamole ER (causes headaches - usually not given) increased risk of side effects
• Aspirin alone (if cant tolerate clopidogrel or aspirin + dipyridamole)
• Most people tolerate low dose aspirin
• 300 mg load and then followed by 100 mg daily
• DAPT -
• don’t use aspirin + clopidogrel for longer than 3 weeks - increases bleeding
• After 3 weeks - continue with either aspirin or clopidogrel alone forever
• Don’t use ticagrelor alone (not better than aspirin)
• DAPT: NOT for low risk TIA or Big strokes –> only for minor stroke and high risk TIA

Question 8

What long-term therapy is recommended for secondary stroke prevention?

Answer 8

- Lower high blood pressure
ACE inhibitors, ARBs, CCB, thiazide diuretics 
- Stop smoking 
- Lower cholesterol 
▪ Start statin 48hours after symptom onset of stroke - all patients regardless of cholesterol levels  (acute phase of stroke) 
- Being more active 
- Eating healthily 
- Lower alcohol intake 
- Good diabetes control

Question 9

How would you manage the administration of the medications you have recommended for a patient with dysphagia?

Answer 9

• Special diets
• Feeding tubes
• Where possible: tablets and capsules: should be administered whole + intact w appropriate food texture and fluid consistency
• Some smaller tablets and capsules can be safely swallowed whole when mixed w food of suitable consistency
• If patient has difficulty swallowing medicine whole: liquids can be used (thickened appropriately)
• If administered with food - medication should be at room temperature
• 1 tablet or capsule (whole, crushed, contents) should be administered per spoonful of food

(see notes)

Question 10

Things a patient with stroke should be aware of/educated about

Answer 10

○ Increasing dose for statin : be aware of any unexplained muscle weakness or pain

○ Antiplatelets: important to prevent future events of stroke, stop clots from forming as blood clots can lead to heart attack or stroke

○ Exercise: prevent risk of stroke events

○ Adhere to medications: people who have had stroke before = more at risk of having recurrent stroke event

○ Look out for signs of stroke: FAST
○ Be aware of signs of bleeding
○ Avoid NSAIDs